DAYTON: Teachers cannot become friendly with students on Facebook and other social networking sites and can't text or send them instant messages under a new policy in one of Ohio's largest school districts.

The Dayton Public Schools policy, which also prohibits teachers from responding to students' attempts at communicating through any personal or professional accounts not approved by the district, was adopted after consulting with the Ohio School Boards Association, the Dayton Daily News reported.

The Dayton district is one of many around Ohio that have contacted the association on the issue of teachers and social media, Sara Clark, the association's deputy director of legal services, told the Associated Press on Wednesday.

''It's a hot topic for school districts right now, and we are getting more calls on it,'' Clark said.

Clark said there is no way of knowing how many districts have such policies. It is up to each district to decide whether to follow any of the association's model that suggests districts bar fraternization between staff and students through electronic media.

School districts can't ignore social media as tools of communication, but they can be misused, Hollie Reedy, the association's chief counsel, told the Dayton Daily News.

Dayton spokeswoman Jill Moberley says the district recognized that social media are growing and wanted ''to develop a forward-thinking policy setting some parameters.''

The head of the Dayton teachers union welcomes the new policy and believes it is ''probably a safe thing for our teachers.''

''We hear stories all the time about kids who, for various reasons, [retaliate] against teachers on social media,'' said David Romick, president of the Dayton Education Association.

Teachers in Missouri have complained that a state ban there on teachers having private conversations with students over Internet sites will hamper their ability to keep in touch with students.

Missouri lawmakers approved the ban after more than 80 Missouri teachers lost their licenses between 2001 and 2005 because of sexual misconduct, the Dayton newspaper reported. Some cases involved exchanging explicit online messages with students.

A judge, concerned about free speech rights, has temporarily blocked the law from taking effect.

A Cincinnati attorney who specializes in media and First Amendment issues said much of the concern in Missouri focuses on whether the law goes too far especially in prohibiting contact between teachers and former students.

''There are sometimes good mentoring relations that couldn't continue if a student went on to college,'' attorney Jack Greiner said.

He said Missouri is the only state he knows of that has handled the issue through statute, but it may not matter whether prohibitions are made at the state or local level.

''I wouldn't be surprised if someone challenges this somewhere in Ohio,'' he told the AP.

Beavercreek City Schools Superintendent Nick Verhoff said his southwest Ohio district's policy authorizes teachers to access social media from the district's network, provided there is an educational purpose and they have the principal's approval. But it prohibits personal access and use of social media, blogs or chat rooms from the district's network.

The Warren school district in Northeast Ohio prohibits teachers from social media contact with students on the district's networks for non-educational purposes and is working on an update that could impose similar restrictions on teachers using personal computers, said district spokesman Aaron Schwab.